import ActivityKit
import Foundation

@MainActor
final class RecordingLiveActivityManager {
    static let shared = RecordingLiveActivityManager()

    private var activity: Activity<RecordingActivityAttributes>?

    private init() {}

    var recoverableSessionID: UUID? {
        activity?.attributes.sessionID
            ?? Activity<RecordingActivityAttributes>.activities.first?.attributes.sessionID
    }

    func start(
        sessionID: UUID,
        title: String,
        sourceName: String,
        elapsedSeconds: TimeInterval
    ) {
        guard ActivityAuthorizationInfo().areActivitiesEnabled else { return }

        Task {
            await endExistingActivities()

            let attributes = RecordingActivityAttributes(
                sessionID: sessionID,
                title: title,
                sourceName: sourceName
            )
            let state = makeState(elapsedSeconds: elapsedSeconds, isPaused: false)

            do {
                activity = try Activity.request(
                    attributes: attributes,
                    content: ActivityContent(state: state, staleDate: nil),
                    pushType: nil
                )
            } catch {
                print("[RecordingLiveActivity] Failed to start: \(error.localizedDescription)")
            }
        }
    }

    func update(elapsedSeconds: TimeInterval, isPaused: Bool) {
        guard let activity else { return }
        let state = makeState(elapsedSeconds: elapsedSeconds, isPaused: isPaused)

        Task {
            await activity.update(ActivityContent(state: state, staleDate: nil))
        }
    }

    func end(elapsedSeconds: TimeInterval) {
        guard let activity else { return }
        self.activity = nil
        let finalState = makeState(elapsedSeconds: elapsedSeconds, isPaused: true)

        Task {
            await activity.end(
                ActivityContent(state: finalState, staleDate: nil),
                dismissalPolicy: .immediate
            )
        }
    }

    private func endExistingActivities() async {
        for existingActivity in Activity<RecordingActivityAttributes>.activities {
            await existingActivity.end(nil, dismissalPolicy: .immediate)
        }
    }

    private func makeState(
        elapsedSeconds: TimeInterval,
        isPaused: Bool
    ) -> RecordingActivityAttributes.ContentState {
        RecordingActivityAttributes.ContentState(
            timerStartDate: Date().addingTimeInterval(-elapsedSeconds),
            elapsedSeconds: elapsedSeconds,
            isPaused: isPaused
        )
    }
}